For the first time ever, scientists were able to detect a magnetic field just outside the event horizon of the black hole at the Milky Way center, known as Sgr A* (Sagittarius A-star).
The majority of people believe that black holes are massive vacuum machine-like cosmic objects that engulf everything that comes close to them. The truth is that big black holes found at the center of galaxies resemble engines that transform energy from infaling matter to strong radiation that is able to shine brighter than all the nearby stars combined.
Black holes are theorized to be powered by magnetic fields. If a black hole is projecting a circular movement, it can produce intense jets that fire up across thousands worth of light years and influence the features of all galaxies.
"Understanding these magnetic fields is critical," said Michael Johnson, lead author of the study from the Harvard-Smithsonian Center for Astrophysics. He added that no one has ever cleared up the puzzle of magnetic fields until now.
The main factor that made the discovery possible is the Event Horizon Telescope (EHT), which is an international network of radio telescopes that are connected to work as a single device that is so massive, it is the same as the size of the Earth.
Bigger telescopes can provide more precise details and for this, the EHT can fully resolve features that are as tiny as 15 micro-arcseconds. For comparison, an arcsecond is 1/3600 of a degree and 15 micro-arcseconds are tantamount to seeing a golf ball on the moon.
Sgr A* has a weight of about four million times the Earth's sun, yet the event horizon surrounding it is just only eight million miles, a measurement that is smaller than Mercury's orbit.
With a distance of approximately 25,000 light years away from Earth, the size of Sgr A* is equivalent to 10 micro-arcseconds across. The intensity of the black hole swerves light and enlarges the event horizon, giving it a magnified rate of 50 micro-arcseconds, which is something that EHT can resolve without much difficulty.
The team of astronomers who discovered the magnetic field conducted their observations at wavelengths of 1.3 millimeters and determined how linearly polarized the light was. Polarized light is released by electrons orbiting the magnetic field lines, which enable it to directly outline the magnetic field's structure.
The researchers discovered that magnetic fields in some areas near the black hole are mixed up just like intertwined pasta, with Johnson even saying they appear to be "dancing all over the place."
Other regions, however, are more organized, probably because these are where jets are produced.
The study was published in the journal Science on Friday, Dec. 4.
